When you say you just started, what kind of discs are you throwing right now and with what kind of success?
Regarding the higher speed number, it roughly translates to how hard YOU need to throw it to get it to do what it is designed to do.
Starting off with a midrange as your "driver" isn't a bad course of action.

you don't have any putters or midranges?
The sidewinder isn't a bad first driver, but at this stage, you'll probably get better distance out of a Shark or Stingray (Innova examples). Throwing speed 4 or 5 discs will help you develop decent form better than erratically flinging the higher speed discs trying to go for max distance. Then, go with Streets' recommendation if you want to stick with Innova and get yourself a DX Leopard.

Sorry I just listed my driver's. I have a few others. A guy at work bought a bunch of disc then didn't like to play so I bought his. I have a champion panther,champion sidewinder, champion banshee, star TL, Z glide, DX roc , champion beast, star skeeter pro leopard and a star leopard. All were allmost new and I figured it was worth the 20 bucks he wanted

Sorry I just listed my driver's. I have a few others. A guy at work bought a bunch of disc then didn't like to play so I bought his. I have a champion panther,champion sidewinder, champion banshee, star TL, Z glide, DX roc , champion beast, star skeeter pro leopard and a star leopard. All were allmost new and I figured it was worth the 20 bucks he wanted

The bolds are what I suggest starting with.
$20 is a great deal for all those!